U.S. patent number 7,162,896 [Application Number 10/926,931] was granted by the patent office on 2007-01-16 for apparatus for checking the formation of scale, and water-carrying appliance.
This patent grant is currently assigned to BSH Bosch und Siemens Hausgeraete GmbH. Invention is credited to Rudiger Eiermann, Helmut Jerg.
United States Patent |
7,162,896 |
Eiermann , et al. |
January 16, 2007 |
Apparatus for checking the formation of scale, and water-carrying
appliance
Abstract
An apparatus allows monitoring the formation of scale. The
apparatus makes it possible to determine the degree of water
hardness or a tendency of the degree of water hardness to change
over time and to take measures for adjusting the desired degree of
water hardness accordingly. A translucent or transparent element
has two end surfaces, at least one element emitting an optical
signal, and at least one element receiving an optical signal. The
element emitting the optical signal and the element receiving the
optical signal are directly adjacent to the end surfaces of the
transparent element, and the end surfaces are disposed such that
they remain free of scale build-up at all times.
Inventors: |
Eiermann; Rudiger (Syrgenstein,
DE), Jerg; Helmut (Giengen, DE) |
Assignee: |
BSH Bosch und Siemens Hausgeraete
GmbH (Munich, DE)
|
Family
ID: |
27740424 |
Appl.
No.: |
10/926,931 |
Filed: |
August 26, 2004 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20050046826 A1 |
Mar 3, 2005 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
PCT/EP03/01328 |
Feb 11, 2003 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Feb 26, 2002 [DE] |
|
|
102 08 214 |
|
Current U.S.
Class: |
68/56; 134/58D;
134/57D; 134/113 |
Current CPC
Class: |
A47L
15/4229 (20130101); A47L 15/4297 (20130101); G01N
21/552 (20130101) |
Current International
Class: |
B08B
13/00 (20060101) |
Field of
Search: |
;134/56D,57D,58D,113 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
35 43 155 |
|
Jun 1986 |
|
DE |
|
196 26 203 |
|
Jan 1998 |
|
DE |
|
197 14 695 |
|
Oct 1998 |
|
DE |
|
197 40 266 |
|
Mar 1999 |
|
DE |
|
198 25 981 |
|
Dec 1999 |
|
DE |
|
0 966 914 |
|
Dec 1999 |
|
EP |
|
0 972 486 |
|
Jan 2000 |
|
EP |
|
2 105 034 |
|
Mar 1983 |
|
GB |
|
59-23221 |
|
Feb 1984 |
|
JP |
|
59-34135 |
|
Feb 1984 |
|
JP |
|
60-135749 |
|
Jul 1985 |
|
JP |
|
3-258385 |
|
Nov 1991 |
|
JP |
|
6-22897 |
|
Feb 1994 |
|
JP |
|
6-86906 |
|
Mar 1994 |
|
JP |
|
00/46572 |
|
Aug 2000 |
|
WO |
|
Other References
Europena Patent Office 0 966 914 Jun. 1999. cited by examiner .
European Patent Office 0 370 238 May 1990. cited by examiner .
European Patent Office 1 180 344 Aug. 2001. cited by
examiner.
|
Primary Examiner: Stinson; Frankie L.
Attorney, Agent or Firm: Warnock; Russell W. Loest; Craig
J.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuing application, under 35 U.S.C. .sctn. 120, of
copending international application No. PCT/EP03/01328, filed Feb.
11, 2003, which designated the United States; this application also
claims the priority, under 35 U.S.C. .sctn. 119, of German patent
application No. 102 08 214.6, filed Feb. 26, 2002; the prior
applications are herewith incorporated by reference in their
entirety.
Claims
We claim:
1. An apparatus for configured for determining a scale build-up in
an appliance, comprising: a translucent element formed with first
and second terminating surfaces and having a chamber region; at
least one optical-signal-emitting element disposed at and directly
adjoining said first terminating surface; at least one
optical-signal-receiving element disposed at and adjoining said
second terminating surface, wherein said terminating surfaces are
disposed to not be subject to scale deposits; and a valve disposed
to selectively empty a chamber region surrounding said translucent
element, and a heating element commonly operating said valve and
drying said translucent element.
2. An apparatus for checking a formation of scale, comprising: a
translucent element formed with first and second terminating
surfaces; at least one optical-signal-emitting element disposed at
and directly adjoining said first terminating surface, said
translucent element forming a light carrying path between its first
and second terminating surfaces operable along which travels light
emitted by said at least one optical-signal-emitting element; at
least one optical-signal-receiving element disposed at and
adjoining said second terminating surface, wherein said terminating
surfaces of said translucent element are disposed to not be subject
to scale deposits; and means for alternately disposing said
translucent element in a wetting condition in which said
translucent element is wetted by a washing liquid and a deposition
condition in which contact between said translucent element and the
washing liquid is controlled to effect the deposition of scale on
said translucent element, said at least one optical-signal-emitting
element being operable, in the deposition condition of said
translucent element, to emit light that travels along said light
carrying path of said translucent element and said at least one
optical-signal-receiving element being operable, in the deposition
condition of said translucent element, to receive light emitted by
said at least one optical-signal-emitting element that has traveled
along said light carrying path of said translucent element.
3. The apparatus according to claim 2, wherein said translucent
element is a selected one of a rod-shaped element having a helical
form and a rod-shaped element having a non-helical form.
4. The apparatus according to claim 2, wherein said means for
alternately disposing said translucent element in a wetting
condition and a deposition condition includes a chamber region in
which said translucent element is located.
5. The apparatus according to claim 4, wherein the water-carrying
appliance is a household appliance and said chamber region is
formed with at least one opening open into an interior of the
household appliance.
6. The apparatus according to claim 5, said means for alternately
disposing said translucent element in a wetting condition and a
deposition condition includes a valve disposed at said chamber
region for selectively emptying said chamber region.
7. A dishwasher, comprising: means for carrying water in which
items to be washed can be disposed; and an apparatus for checking a
formation of scale having: (a) a translucent element formed with
first and second terminating surfaces, (b) at least one
optical-signal-emitting element disposed at and directly adjoining
said first terminating surface, said translucent element forming a
light carrying path between its first and second terminating
surfaces operable along which travels light emitted by said at
least one optical-signal-emitting element, (c) at least one
optical-signal-receiving element disposed at and adjoining said
second terminating surface, wherein said terminating surfaces of
said translucent element are disposed to not be subject to scale
deposits, and (d) means for alternately disposing said translucent
element in a wetted condition in which said translucent element is
wetted by a washing liquid and a deposition condition in which
contact between said translucent element and the washing liquid is
controlled such that scale forming matter in the washing liquid is
deposited as scale on said translucent element and the scale thus
deposited on said translucent element is not carried away by the
washing liquid, said at least one optical-signal-emitting element
being operable, in the deposition condition of said translucent
element, to emit light that travels along said light carrying path
of said translucent element and said at least one
optical-signal-receiving element being operable, in the deposition
condition of said translucent element, to receive light emitted by
said at least one optical-signal-emitting element that has traveled
along said light carrying path of said translucent element.
8. The apparatus according to claim 7, wherein said means for
alternately disposing said translucent element in a wetted
condition and a deposition condition controls the wetting of said
translucent element during said wetted condition such that the
washing liquid carries away from said translucent element at least
a portion of the scale that had been deposited on said translucent
element during an earlier disposition of said translucent element
in its deposition condition.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an apparatus for checking the
formation of scale, comprising a translucent element with two
terminating surfaces, and also comprising at least one
optical-signal-emitting element and at least one
optical-signal-receiving element, and to a water-carrying
appliance, in particular for domestic use.
For the use of water-carrying household appliances, in particular
household dishwashers, the washing liquid is softened in a
water-softening configuration, prior to each washing operation, in
regions with a high degree of water hardness. If use is made of
insufficiently softened water, characteristic lime deposits form,
during the drying operation, on the articles which are to be
washed. These deposits detract from the appearance, in particular,
of glasses and shiny stainless-steel surfaces. In order to avoid
these lime deposits, the ion exchanger is usually regenerated on a
regular basis, with the result that no lime deposits may be
expected in the washing operation following the regenerating
operation. Since the softening quality of the ion exchanger
decreases on a constant basis between the regenerating operations,
and the frequency of scale build-up thus increases, it is desirable
for a tendency toward scale build-up and density to be detected in
good time, in order for appropriate regenerating measures to be
taken.
German published patent application DE 198 25 981 discloses a
process and an apparatus for softening water in a
program-controlled water-carrying household appliance. There,
during one sub-program, a regenerating operation for an ion
exchanger is carried out by virtue of a quantity of brine being
added and, during a further sub-program, a washing program is
carried out.
For carrying out the prior art process, a change in the water
hardness as a result of lime deposits on a translucent surface is
measured by a sensor with an optical-signal-emitting element and an
optical-signal-receiving element. A point in time for carrying out
the regenerating operation is determined in dependence on the lime
deposit measured, a control unit processing the signals
correspondingly and initiating a regenerating operation.
It has proven to be disadvantageous in the case of the prior art
apparatus that, in addition to lime deposits on the translucent
surface giving corresponding measured values, it is also the case
that particles of dirt and other elements of dirt extending over a
relatively large surface area adversely affect the path of
radiation between the emitting and receiving elements and thus
result in falsified measurement results. It has also proven to be
disadvantageous that even opacity of the lens of the
optical-signal-emitting elements and/or of the
optical-signal-receiving elements give measured values, even if the
optical properties of the translucent surface remain unchanged,
which point to the fact that regeneration is required.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a device
for checking for scale buildup and a water-conducting appliance
which overcome the above-mentioned disadvantages of the
heretofore-known devices and methods of this general type and which
make it possible to determine the formation of scale or a tendency
towards the formation of scale and to achieve corresponding
measures for setting the desired formation of scale.
With the foregoing and other objects in view there is provided, in
accordance with the invention, an apparatus for checking a
formation of scale, comprising:
a translucent element formed with first and second terminating
surfaces;
at least one optical-signal-emitting element disposed at and
directly adjoining the first terminating surface; and
at least one optical-signal-receiving element disposed at and
adjoining the second terminating surface;
wherein the terminating surfaces are disposed to not be subject to
scale deposits.
In other words, the apparatus according to the invention for
checking the formation of scale, comprising a translucent element
with two terminating surfaces, also has at least one
optical-signal-emitting element and at least one
optical-signal-receiving element. The translucent element is
configured such that the optical-signal-emitting and the
optical-signal-receiving elements each directly adjoins a
respective one of the terminating surfaces of the translucent
elements, and the terminating surfaces are protected so that remain
free of scale.
The translucent element is advantageously a rod-like design or,
starting from a rod shape, of helical design. The translucent
element is expediently arranged in a chamber region, the chamber
region having at least one opening which opens out into an interior
of a water-carrying household appliance, preferably of a
dishwashing compartment, and also having a valve which is suitable
for emptying the chamber region.
The valve in the chamber region is expediently operated
electromagnetically, it preferably being possible for the valve to
be driven via an actuating element with memory effect.
The apparatus according to the invention is expediently arranged in
the inner door of a water-carrying household appliance, in
particular of a dishwasher, and has a corresponding opening through
which the washing liquid can circulate and/or can enter into the
chamber region.
Following the chamber region has been filled with washing liquid
during the washing phase, a corresponding quantity of washing
liquid will adhere to the translucent element, which preferably
consists of glass, particularly advantageously of boron silicate,
and, when the drying operation commences, will possibly leave
behind a corresponding deposit, in other words a lime deposit. The
extent of the scale build-up, in particular of the lime deposits,
is measured according to the invention via an optical signal. The
measurement is based on the following physical phenomenon.
The light (for example infrared light) emitted by the
optical-signal-emitting element enters into the translucent element
via the first terminating surface and, on account of the reflection
taking place in the translucent element, is constantly reflected at
the boundary surface between the translucent element and the
surroundings, i.e., the enclosing atmosphere. The light beam thus
radiates, substantially without refraction and scattering losses,
through the translucent element and, finally, passes out through
the second terminating surface and enters into the
optical-signal-receiving element. The total reflection taking place
in the translucent element dictates the brightness value, which
corresponds to a certain energy value. A difference in energy
between the optical-signal-emitting element and the
optical-signal-receiving element is based on a certain radiation
capacity of the translucent element and is correspondingly taken
into account during processing of the signal value.
When the translucent element is wetted by washing liquid and
corresponding deposits, e.g. lime deposits, adhere to the
translucent element during the drying operation, the refractive
index between the translucent element and the directly adjoining
deposit layer changes in these regions such that the number of
total reflections at the boundary layer of the translucent element
decreases. This is because a light beam impinges at a certain angle
on the boundary surface of the translucent element and, if this
region of the translucent element is covered by a deposit layer, a
certain amount of the light beam passes out of the translucent
element and is not reflected into the translucent-element. Total
reflection occurs only where the angle of incidence is less than
the critical angle. Since the optical-signal-receiving element
measures the energy intensity or light intensity of the light
passing out of the translucent element, the light intensity
received is associated with a corresponding scale build-up, e.g. a
lime deposit, on the translucent element.
The apparatus according to the invention can thus determine the
beginning of deposit formation on the translucent element, which
preferably consists of glass, with the result that appropriate
measures, e.g., in the case of lime deposits being established, for
water softening, can be taken in good time. According to the
invention, deposits, e.g. lime deposits, on the translucent element
can already be established before this is visible to the human eye
on glassware.
Once a certain deposit-threshold value, in particular one for lime
deposits, has been established, the regenerating process for the
ion exchanger is started and the normally very thin deposits, in
particular lime deposits, on the translucent element are cleaned
using newly softened water and possibly washing agent. In order to
achieve a reproducible circulating-flow structure in the chamber
region, the chamber region has an opening which is preferably
designed such that it is not possible for any food residues to
penetrate into the chamber region. A lattice-like covering is
preferably provided for this purpose, wherein case the respective
lattice openings should be dimensioned such that customary,
frequently encountered food-residue particles, for example pips of
citrus fruits, cannot pass through.
Once the chamber region has been filled with washing liquid, the
latter remains in the chamber region for a predetermined period of
time, in order for the constituent parts located in the washing
liquid, in particular hardness salts dissolved therein, to be given
time for depositing on the translucent element. Before emptying the
chamber region, the apparatus according to the invention has a
valve which is arranged such that the chamber region can be emptied
completely. The valve may be formed by conventional magnetic valves
or also by valves which can be actuated mechanically. Particularly
advantageous valves are ones which can be actuated by actuating
elements made of memory metal.
In order realistically to address a depositing process, e.g. the
lime-depositing process, as takes place during the drying phase in
the dishwashing compartment of the dishwasher, the apparatus
according to the invention has a heating element which heats the
moist atmosphere in the chamber region and thus dries the
translucent element. During this drying process, if water is not
fully softened, a lime deposit forms on the translucent element and
this lime deposit is determined by way of the above-described
measuring process.
Other features which are considered as characteristic for the
invention are set forth in the appended claims.
Although the invention is illustrated and described herein as
embodied in an apparatus for checking the formation of scale, and
water-carrying appliance, it is nevertheless not intended to be
limited to the details shown, since various modifications and
structural changes may be made therein without departing from the
spirit of the invention and within the scope and range of
equivalents of the claims.
The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be
best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of the functioning of the
translucent element and of the two signal-receiving and
signal-emitting elements;
FIGS. 2A and 2B are schematic illustrations of the translucent
elements, showing the functional principle of the apparatus
according to the invention;
FIG. 3 is a sectional view illustrating a preferred embodiment of
the apparatus according to the invention;
FIG. 4 is an elevational view of the preferred embodiment according
to FIG. 3; and
FIG. 5 is a plan view of the preferred embodiment according to
FIGS. 3 and 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first,
particularly, to FIG. 1 thereof, there is shown an
optical-signal-emitting element 4 and an optical-signal-receiving
element 5 connected to one another via a translucent element 2. A
U-shape has been selected for the translucent element 2. In the
case of the preferred embodiment that is shown in FIGS. 3, 4 and 5,
the translucent element is of helical design and thus has the
advantage of using a relatively long light-carrying path for
measuring purposes. The translucent element may also be designed
without any curvature, in particular the design of a rod-like
translucent element may be advantageous. If use is made of a
rod-like translucent element, it is possible to arrange a plurality
of elements one beside the other in the chamber region, in order to
achieve, for example, a certain degree of redundancy during the
measuring operation. If use is made of a plurality of translucent
elements, furthermore, the light spectrum may be selected to be
broader. In other words, it is possible to vary the preferred
infrared range in the case of the individual translucent elements
and the optical-signal-emitting-receiving elements connected
thereto.
The physical phenomenon on which the apparatus according to the
invention is based is illustrated in FIGS. 2A and 2B. The light
emitted by the optical-signal-emitting element 4 has an energy
level E.sub.1 and, having passed through the translucent element 2,
has an energy level E.sub.2 at the optical-signal-receiving element
5. If, as illustrated in FIG. 2A, the translucent element 2 does
not contain any contamination, such as, lime deposits or other
scale build-up, essentially all the light beams which are emitted
into the translucent element 2 by the optical-signal-emitting
element 4 are reflected on account of the total reflection between
the translucent element and the surrounding atmosphere, until the
optical-signal-receiving element 5 is reached, and do not leave the
translucent element. As a result, the energy level E.sub.1
corresponds substantially to the energy level E.sub.2, with the
result that, upon determination of these two energy levels, it is
established that there is no contamination or scale build-up, i.e.,
lime deposit, on the translucent element 2.
If the translucent element has insufficiently softened water
circulating around it, and is then dried, this results in the
formation of lime deposits 10 which at least partially cover the
outer surface of the translucent element 2. Upon transillumination
of the translucent element 2, where the optical-signal-emitting
element 4 emits radiation at an energy level E.sub.3, the
optical-signal-receiving element 5 receives an energy level
E.sub.4. In correspondence with the lime deposit 10, it can be
established that the energy level E.sub.4 is significantly lower
than the energy level E.sub.3. As a result, the determination of
the energy level E.sub.4 relative to the energy level E.sub.3 makes
it possible to establish the degree of lime deposit or of
contamination on the translucent element 2.
For example, in order to process the energy level E.sub.4, the
value of the latter is inverted and it is then present as a
positive voltage. The program-control unit connected downstream, in
a signal flow direction, that is, of the optical-signal-receiving
element processes this positive measuring signal and, on account of
measurement data provided, derives a corresponding measurement
result. Depending on setting and program control, when a threshold
value or degree of contamination is reached, regeneration of the
ion exchanger is activated, in order thus for softened water of
appropriate quality to be available for the next washing-program
sequence.
FIG. 3 shows a sectional illustration through a preferred
embodiment of the present invention, which is used in a
water-carrying household appliance. The apparatus 1 according to
the invention is preferably installed in the inner door 14 of a
dishwasher (preferably snapped into place and held with
circumferentially disposed tabs) and, for sealing between the
dishwashing compartment and the inside of the door, is sealed via
corresponding sealing elements 12. During the washing program,
washing liquid flows, along the arrow direction 6, into the chamber
region 3, fills the latter and thus wets the translucent elements
2. The latter have a helical configuration or design. Once wetting
has taken place, the chamber region 3 is emptied via the valve 7
and the chamber region 3 is heated by means of heating element 9
such that the wetted translucent element 2 dries. If the wetting
operation takes place with insufficiently softened water, a lime
deposit forms on the translucent element 2, this deposit being
determined by means of the above-described measuring method, using
the elements 4, 5. Prior to the drying operation, the chamber
region 3 is expediently flooded and emptied a number of times, in
order for reproducible results thus to be obtained. The heating
element 9 used is preferably a so-called PTC (Positive Temperature
Coefficient) element, which forms certain flow characteristics and
is capable of heating the chamber region 3 to a uniform temperature
of, for example, above 100.degree. C. A so-called memory wire 13 is
provided for actuating the valve in the preferred embodiment
according to FIG. 3, this memory wire changing shape when heated,
i.e. when a certain current flows through, and opening the valve 7.
The valve 7 expediently comprises an elastomeric region 15 and a
pin-like element 16 which, on account of the change in shape of the
memory wire 13, changes its position and thus opens the valve 7.
Following cooling of the memory wire 13, the force applied by the
restoring spring 8 predominates, and moves the pin 16, together
with the elastomeric region 15, such that the valve 7 is
closed.
The rear view of the apparatus according to the invention which is
seen in FIG. 4 illustrates the memory wire 13 and the restoring
spring 8. The figure further illustrates the preferred round
configuration of the apparatus 1 according to the invention.
FIG. 5 shows a top view of the apparatus 1 according to the
invention, an illustration being given, in particular, of the
chamber region of the opening 6. The region is advantageously
designed and dimensioned such that food residues cannot pass into
the chamber region 3 of the apparatus 1 according to the
invention.
The present invention provides an apparatus 1 which makes it
possible to determine the formation of scale, e.g. the degree of
water hardness, or a tendency towards the formation of scale, e.g.
the degree of water hardness, and to achieve corresponding measures
for setting the desired formation of scale, e.g. the desired degree
of water hardness.
* * * * *